Quantitative responsiveness of murine hemopoietic populations in vitro and in vivo to recombinant multi-CSF (IL-3)

Abstract

Purified, bacterially synthesized, recombinant Multi-CSF (rMulti-CSF) exhibited in vitro proliferative effects identical to those of native Multi-CSF on a broad range of progenitor cells from normal murine bone marrow and on the continuous cell line FD-CP1. The injection into normal adult mice of 6-200 ng purified rMulti-CSF three times daily for six days induced dose-related rises in peritoneal macrophages, neutrophils, and eosinophils, and in the spleen weight and content of megakaryocytes, mast cells, and progenitor cells, some response being detectable with the lowest dose injected. No Multi-CSF was detected in the serum, organ extracts, or organ-conditioned medium from normal or endotox..